[Detection of mycobacteria by polymerase chain reaction].

The polymerase chain reaction (PCR) was used to detect mycobacterial DNA sequences in the cultured or the clinical specimens. Four oligonucleotide primers derived from the sequence of a gene coding 65-kilodalton antigen of Mycobacterium tuberculosis amplified DNA samples of all the 11 species of mycobacteria tested. Serial dilution of M. bovis BCG showed that DNA extracted from only 12 bacilli was enough for the detection by PCR method. However, mycobacteria in sputum were detected by PCR when more than 10(3) bacilli were present. The PCR method may become a useful tool for the rapid diagnosis of mycobacterial infections.